device.h

#define SEEK_SET        0
#define SEEK_CUR        1
#define SEEK_END        2

struct device {
    int32_t (*dev_open)(uint32_t flags);
    int32_t (*dev_read)(void *buf, uint32_t size);      /* size is ignored for block devices */
    int32_t (*dev_write)(void *buf, uint32_t size);
    int32_t (*dev_close)(void);
    int32_t (*dev_ioctl)(uint32_t request, void *pval);
    void *ptr;                      /* pointer to device specific data
                                (e.g struct fs_blkdevice, struct blk_device
                                or struct chr_device) */
};

int32_t hf_dev_open(struct device *dev, uint32_t flags);
int32_t hf_dev_read(struct device *dev, void *buf, uint32_t size);
int32_t hf_dev_write(struct device *dev, void *buf, uint32_t size);
int32_t hf_dev_close(struct device *dev);
int32_t hf_dev_ioctl(struct device *dev, uint32_t request, void *pval);